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SS Freeze Plugs Fitment

El.Padrino

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I have a 383 block (‘68) and fully disassembled, removed the brass plugs that were in and flushed the block.

I ordered the stainless steel freeze plug kit from 440source.

I dry fitted the plugs and some bores of the blocks are larger than others.
For example the one pictured is on the driver side. Block hole diameter is 1.61“ and the SS freeze plug only is 1.64“.
I did not hammer it in yet, on the pic the plug just rests in the hole by hand. A slight punch will knock it and that‘s it. I am afraid this won‘t be enough to seal against the block and will cause me a leak.

Just can add some high temp sealant or silicone..

Anyone had the same experience? Any suggestions how to move on?

JeXevZE.jpg
 
No idea why you’d want stainless in that application.
Brass is what I’d use
 
i liked the look of the stainless steel plugs thats why i bought them (and the set came with other plugs too).

The brass won‘t be of a different size?! It is more the bore of the engine block that are very different.
 
You sure you have those measurements right .030" difference? Or is it .003"?
 
Install them with aviation grade permatex---don't use silicon
 
Aren't press on bearings about .003"?
Edit: .003 interference fit?
 
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I think those are just referred to as steel plugs, not sure about the stainless part.

I always use Indian Head on them. Some are a big more snug than others. I had a 440 that had one hole where my plug fell through. I had to get a series of plugs 1/64 up size one at a time until I found one that fit.

I don’t think brass or steel makes a difference in size. You’ll probably run into the same thing. I’ve seen brass kits that are deep cups, that may help.
 
Just went through this with a 440 I'm building. the standard brass plugs went in too easy and too far. So I replaced them with Melling brass plugs that are deeper and used permatex # 2 for sealing. Melling part # MPE614BR. The core plugs on the sides of the block should be 1 5/8" dia.
 
Stainless expands slower due to the higher melting point. Brass will expand sooner, thus maintaining the seal.
 
You could always make up a simple mandrel to expand the new plugs a bit more before installation.
 
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